Consolidated Statement of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Cash Flows [Abstract]
Net income	$ 744,959	$ 731,773	$ 760,790
Adjustments to reconcile net income from continuing operations to cash provided from continuing operations:
Loss (income) from discontinued operations, net of income taxes	0	0	92
Increase (decrease) in future policy benefits	854,770	798,936	661,567
Increase (decrease) in other policy benefits	18,144	33,810	15,900
Deferral of policy acquisition costs	(906,247)	(822,985)	(753,661)
Amortization of deferred policy acquisition costs	603,838	575,770	551,726
Change in current and deferred income taxes	71,919	88,157	68,588
Realized (gains) losses	(59,319)	4,371	(20,621)
Other, net	109,616	66,602	62,194
Net cash provided from (used for) continuing operations	1,437,680	1,476,434	1,346,575
Net cash provided from (used for) discontinued operations	0	0	17,299
Cash provided from (used for) operating activities	1,437,680	1,476,434	1,363,874
Cash provided from (used for) investing activities:
Fixed maturities available for sale—sold	116,656	52,681	79,108
Fixed maturities available for sale—matured or other redemptions	310,991	416,321	840,222
Other long-term investments	36,346	42,990	5,134
Total investments sold or matured	463,993	511,992	924,464
Acquisition of investments:
Fixed maturities—available for sale	(1,004,384)	(1,262,434)	(1,552,956)
Other long-term investments	(258,296)	(266,230)	(123,332)
Total investments acquired	(1,262,680)	(1,528,664)	(1,676,288)
Net (increase) decrease in policy loans	(5,255)	(8,887)	(25,426)
Net (increase) decrease in short-term investments	38,637	(69,497)	34,003
Additions to properties	(38,244)	(41,756)	(42,203)
Other investing activities	(56,700)	(7,051)	32
Investments in low-income housing interests	(53,121)	(37,867)	(23,893)
Cash provided from (used for) investing activities	(913,370)	(1,181,730)	(809,311)
Cash provided from (used for) financing activities:
Issuance of common stock	69,826	48,093	83,163
Cash dividends paid to shareholders	(80,043)	(78,192)	(74,188)
Repayment of debt	(300,000)	(386,875)	(6,875)
Proceeds from issuance of debt	325,000	700,000	0
Payment for debt issuance costs	(7,687)	(5,844)	0
Net borrowing (repayment) of commercial paper	74,974	(34,445)	(11,610)
Acquisition of treasury stock	(541,435)	(443,866)	(459,569)
Net receipts (payments) from deposit-type products	(64,238)	(72,928)	(121,429)
Cash provided from (used for) financing activities	(523,603)	(274,057)	(590,508)
Effect of foreign exchange rate changes on cash	(3,391)	(1,733)	(9,148)
Net increase (decrease) in cash	(2,684)	18,914	(45,093)
Cash at beginning of year	94,847	75,933	121,026
Cash at end of year	$ 92,163	$ 94,847	$ 75,933